Locking means for chair controls



United States Patent [72] Inventors Ralph F. Anderson; 2,476,226 7/1949 Schwinn 297/195 Richard C. Henson, Rockford, Illinois 2,778,409 1/1957 Soderberg 279/304 [211 App]. No. 761,424 2,991,125 7/1961 Lie 297/304 [22] Filed Sept. 23,1968 3,386,770 6/1968 Williams 297/304 [45] Patented Dec. 8, 1970 3,250,567 5/1966 Parrott 297/304 73] Assignee Keystone Consolidated Industries, Inc. FOREIGN PATENTS 1 054 358 4/1959 German 297/373 a corporation of Delaware y I Primary Examiner--Reinaldo P. Machado w Attorney-Wilson & Geppert [54] LOCKING MEANS FOR CHAIR CONTROLS 3 n ABSTRACT: In a chair control of the type having tiltable back [52] US. Cl. 297/373, and tensiomadjusting means, the chair back having a pivotauy 297,300 mounted back bracket with locking means including a pair of llll- A470 1/025 adjustment slides each having inwardly projecting and radially [50] Field of Search 297/300, exending -m f i fl ki engagement with radially 373,304,195305 extending serrations on the adjacent sides of the pivotally References Cited mounted back bracket, and manual adjusting means for forcing the serrations on the slides into interlocking engagement UNITED STATES PATENTS with the serrations on the sides of the back bracket and 1,224,263 5/1917 Bolens 297/373 thereby securely retaining the bracket and the chair back in 2,137,335 11/1938 Gabb 297/373 the desired adjusted position.

PATEN TED nu: 8 mm I SHEEI 2 OF 2 LOCKING MEANS FOR CHAIR CONTROLS The present inventionrelates to chair controls in which the back of the 'chair'is tiltable and adjustable and to novel locking means for securely and positively retaining the back and its supporting bracket in a predetermined adjusted position. It is an important objectof the present invention to provide in a chair control ofthe tiltable type having a tiltable back supporting bracket and back,=novel adjusting and locking means for securely anchoring the back and its pivoted back support in adjusted positionby radially extending interlocking means.

In the disclosedembodiment, the chair control is of the torsion bar principle in which .the back bracket affixed to and carrying the tiltable backof'the chair is of substantially U- shape'with itsspaced sides pivotally mounted adjacent one end to the spaced arms of a supporting member, each side of the back bracket adjacent its other end having an arcuate slot receiving a-crossbolt and radial serrations adjacent the other end of these sides, and each arm of the supporting member having an opening and carrying an adjustment slide also having an opening for the bolt andradial serrations for interlocking engagement with the'adjoining serrations on the sides of the back bracket, the bolt passing through the slot in each side of the back bracket, the opening in each slide and the opening in each arm of the supporting member whereby when the bolt is manually tightened after adjustment of the back bracket, the' back bracket and the back are securely retained against displacement.

novel locking means forthe back bracket..

FIG. 4 is an enlarged-top plan view of the back bracket.

FIG. 5 is an elevational view of one exterior side of the back bracket. v I

FIG. 6 isa front elevational view of the back bracket.

FIG. 715 a vertical cross-sectional view taken on the line 7-7 ofFlG. 6. I I

FIG. 8 is a side elevational view of the right-hand adjustable slide ofthe locking means.

FIG. 9 is an'end elevational view of FIG. 8.

FIG. 10 is a side elevational view of the left-hand adjustable slide of the locking means.

FIG. 11 is an end elevational view of FIG. 10.

The present novel locking means for an adjustable back support is illustrated in the present drawings in an embodiment of chair control 10 for a tilting chair construction having a conventional base support on casters, wheels or glides and wherein the seat and back can be tilted with respect to the base.

The-base has a threaded spindle or post 1] adjustable in an encompassing vertical hub or. sleeve 12 and an internally threaded hand wheel 13 for locking the spindle in a vertically adjusted position. The upper end of the spindle is anchored in and projects through an opening in a lower U-shaped yoke 14 and into an aligned opening in an embossment 15 in a larger inverted U-shaped yoke 16 receiving the yoke 14, the spaced overlappingsides 17 of the yoke 16 being bolted or otherwise rigidly connected to the sides of the yoke l4.

The forwardly extended ends 18 of the sides 17 of the larger Q yoke 16 are rigidly secured to an elongated horizontal tubular member 19 through which projects a square cross-sectional torsion bar 20 as disclosed in the Finn Lie U.S. Pat. No. 2,991,125, of July-4, 1961, with the ends of the tubular member crimped about or otherwise affixed to the ends of this torsion bar. The opposite ends of the tubular member 19 and torsion bar 20 project; through encompassing and telescoping spaced sleeves 21 and 22 in which the tubular member 19, its

torsion bar 20 and joined yokes 14 and 16 are rotatable with the outer ends of these sleeves 21 and 22 being anchored in depending flanges 23 of spaced spiders or angle members 24 and 25 affixed to and mounting the chair control assembly 10 to the underside of the base'or bottom of the chair seat 26.

The above torsion bar assembly acts to resiliently cushion rearward tilting of the chair seat 26 against the rearward shifting of the weight of the occupant.

A second torsion bar assembly provides a resilient restraining force tending to oppose backward tilting or counterclockwise movement of the chair back 27 affixed to a back support bracket 28. This second torsion bar assembly, like the first, includes a torsion bar 29. encompassed by a tubular member 31 having its opposite ends rotatably received in spaced telescoping sleeve members 32 and 33 with the outer ends of these sleeve members secured in the depending flanges 23 of the spaced spiders 24 and.25. The inner ends 34 of the sleeve members 32 and 33 terminate adjacent to and the tubular member 31 is rigidly affixed to and intermediate the ends of the spaced arms 35 and 36 of a U-shaped link member 37, the forward end of each arm being pivotally connected to one end of a toggle or link 38 with the other end of each toggle 38 beingpivotally connected to the spaced sides 17 of the yoke 16.

Spanning and affixed at its ends to the arms 35 and 36 adjacent to but rearwardly of the tubular member 31 is an inclined bridging member or support 39 having its depending end bent inwardly to'provide an inturned flange 41 adapted to abut the edge of the base 42 of the upper yoke 16 and provide a stop. Spacers 43 and 44 bridge the sleeve members 21 and 32, and 22 and 33 of the two torsion bar'assemblies and have their ends rigidly affixed to these sleeve members.

The ends of each torsion bar 20 and 29 extend through and beyond the ends of the encompassing tubular members 21 and 22 and 32 and 33, and extend through the tubular members 19 and 31 to which these ends are affixed by crimping or by a plug. One extended end of each torsion bar is received in a tension lever, with one end of the forward torsion bar 20 being received in an end 45 of a front torsion lever 46 and an end of the rear torsion bar 29being received in an end 47 of a rear torsion lever 48. These torsion levers 46 and 48 are pivotally connected at 49 with the end 51 of the forward torsion lever 46 extended rearwardly beyond the pivot and at its rear end 51 adjustably connected to an adjusting screw 52 manually adjusted by the handle 53.

Tightening the screw 52 with its upper end abutting the underside of the horizontal flange of the spider 24 between the V-shaped depressions at 54, pivots the torsion levers 46 and 48 and the connected ends of the-torsion bars 20 and 29 to effect a resilient force in these torsion bars with the back and seat tilting in synchronized action.

The present invention is primarily concerned with the backsupporting bracket 28 and the locking means for rigidly retaining the chair back 27 and its back-support bracket 28 in adjusted position. The back bracket is of substantially L-shape with a rear upstanding bridging portion 54 having inturned spaced flanges 55 and 56 and spaced arms or sides 57 and 58, the latter spanning and pivotally mounted at 59 upon spaced sides 61 and 62 at the U-shaped rear end of the link member 37.

The rear or bridging portion 54 is provided with a longitudinal slot 63 and an adjusting screw 64 for vertical adjustment of the chair back 27.

To pivotally adjust the back bracket 28 on the link member 37 of the chair control 10, the arm 57 is provided with an arcuate slot 65 and the arm 5.8 is also provided with an arcuate I slot 66, both arcuate slots aligned and spaced forwardly of the pivot 59 receiving a bridgingbolt 67, an end of this bolt being threaded to receive an internally threaded spindle or collar 68 having a transverse locking handle 69. Tightening the handle 69 when the back bracket 28 is in adjusted position causes the inner end of the spindle and the head of the bolt 67 to tightly bear against the arms 57 and 58. To securely lock the bracket 28 in pivotally adjusted position, the inner faces of the arms 57 and 58 are provided at the ends adjacent and forwardly of the arcuate slots with radial serrations 71, the arm 57 having the ends of its slot 65 squared to receive the square end of the head of the bolt 67 and the ends of the slot 66 beingrounded.

Slidably mounted on one arm 61 of the link member 37 is a flanged right-hand adjustment slide 72 and on the other arm 62 of this. link member isprovided a flanged left-hand adjustment slide 73, the slide 72; as seen in FIG. 8, having an opening 74which is upwardly offset from the center and radial serrations 75 in the upper portion, and the adjustment slide 73, as seen in FIG. 10, having an opening 76 which is downwardly offset from the center and radial serrations 77"in its lowerportion. These radial serrations 75 and 77 and the openingst74 and 76 are adapted to be horizontally aligned on the arms 61 and 62 of the link member 37' and areadapted to have meshing and locking interengagement with the radial serrations 71 on the inner face o f the anns 57' and 58, when the handle .69 and threaded spindle 68 are tightened. Thus, the back bracket- 28 and the chair back 27 may be quickly adjusted to suitthe occupant when the handlet69 is turned counterclockwise to loosen the bolt 67 and spindle 68 and release from locking engagement the slides 72-and 75 permitting ready adjustment of the tilting movement of the chair back.

We claim:

1. Locking means for a chaircontrol having spaced supporting members for tiltably mounting the, back of the chair, comprising a substantially U-shaped back supporting bracket having spaced arms pivotally mounted adjacent one end on the supporting members, each of said spaced arms having adjacent the opposite end an arcuate slot and inwardly facing radial serrations projecting forwardly from said slot, and adjustment means including a substantially U-shaped' slide mounted on each supporting member facing the serrations on an arm of said bracket and having an opening and radial serrations for interengagement with the serrations on'thc adjacent arm of the back bracket, each slide being slidably mounted for adjustment on a supporting member, and an adjustable locking bolt extending through the arcuate slot in each arm on the back bracket and the aligned-openingsin the slides a'rtd aligned openingsin the supporting members for effecting'im terlockingengagement of the cooperating serrations on.the bracket and the slides when the boltfistightened to securely retain the backbracket and chair back in adjusted position.-

2. Locking means for a chair control as set forth in-claim'll in which the axis for the arcuate slots and the radial serrations is the pivotal mounting for the back bracket with said se'rra: tions being generally horizontal, and said pair of slides providr ing a right-hand and a left-hand slide with the opening for-each slidebeing offset from the center of the slide and the radial serrations projecting away from-and on only one side of the opening.

3. Locking means for a chair control as set forth in claim 1-; in which said support members comprise spaced arms of a U- shaped link on the chair control, and the back bracket is also of substantially U-shape with its spaced arms bridging the arms of the U-shaped link and the pivotal mounting therefore located adjacent the connecting portion of the U-shaped link and the connecting portion ofthe U-shaped bracket. 

